Safety analysis of a railway car under the periodic excitation from the track

A railway derailment is usually an unpredictable event where the damage could range from a simple train delay to a big loss of goods, assets ( rolling stock and permanent way) and, in extreme cases, even human lives. Therefore, Brazil's railways are always implementing actions that minimize the risk of a derailment. One of the main actions is to establish tight maintenance criteria for rolling stock and for track geometry. However, these criteria usually do not consider the vehicle dynamics and the geometry of the permanent way together. Thus, this paper develops a mathematical model of a high capacity railcar together with the flexible support of the track to determine a method of assessing bounce, roll and pitch motions from instrumented wagons, so this method can be used in routine inspections. The mathematical model was satisfactorily validated by comparing the natural frequencies obtained from the model and from a real vehicle tested in the field. In addition, the model results were compared against field measurements from an instrumented wagon and a track geometric vehicle. A strategic method for operational safety analysis was suggested and used, which was able to determine the wavelength of permanent way anomalies that should be given priority for maintenance actions as well as considered when adopting speed restrictions.